Remove the expat and jsoncpp to reduce the binary size.

webrtc/examples/BUILD.gn

 # Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../webrtc.gni")
 if (is_android) {
@@ skipping 509 matching lines @@
       deps += [ "//build/config/linux/gtk" ]
     }
     configs += [ ":peerconnection_client_warnings_config" ]
 
     deps += [
       "//third_party/libyuv",
       "//webrtc/api:libjingle_peerconnection_test_api",
       "//webrtc/api:video_frame_api",
       "//webrtc/base:rtc_base",
       "//webrtc/base:rtc_base_approved",
+      "//webrtc/base:rtc_json",
       "//webrtc/media:rtc_media",
       "//webrtc/modules/video_capture:video_capture_module",
       "//webrtc/pc:libjingle_peerconnection",
       "//webrtc/system_wrappers:field_trial_default",
       "//webrtc/system_wrappers:metrics_default",
     ]
-    if (rtc_build_json) {
-      deps += [ "//third_party/jsoncpp" ]
-    }
   }
 
   rtc_executable("peerconnection_server") {
     testonly = true
     sources = [
       "peerconnection/server/data_socket.cc",
       "peerconnection/server/data_socket.h",
       "peerconnection/server/main.cc",
       "peerconnection/server/peer_channel.cc",
       "peerconnection/server/peer_channel.h",
@@ skipping 82 matching lines @@
 
     deps = [
       "../base:rtc_base",
       "../base:rtc_base_approved",
       "../p2p:libstunprober",
       "../p2p:rtc_p2p",
       "../system_wrappers:field_trial_default",
     ]
   }
 }